Pyparsing offers the ParseElementEnhance subclass DelimitedList for parsing (typically comma-separated) lists:

I wrote a little parser using pyparsing to parse Google-like search strings, like foo AND (bar OR baz) (full code below). Like Google, I would like to make the parser fully fault-tolerant. It should ignore errors and parse as much as it can.

I want to parse strings like alpha OR beta gamma where a missing operator (in this case between beta and gamma a implicit AND is used.